LiftMaster · Garage Door Opener Moderate

1-1 — LiftMaster 1-1 — Safety Sensor Obstructed, Misaligned, or Disconnected

Flash code 1-1 means the safety reversing sensors are obstructed, misaligned, or disconnected (or have broken wiring) for more than a few seconds. Note: a wire SHORTED to the white/common wire is a different code (1-2).

Keep using it?
Yes, with caution
DIY difficulty
Easy
Typical cost
$25-40
Verified against
liftmaster.com ↗

The fix

LiftMaster Safety Sensor Kit (041-0136, replaces 41A5034)

Safety reversing sensors obstructed, misaligned, or wired wrong

$25-40 easy difficulty 30 min Tools: screwdriver

Diagnose first: Before buying a new kit, just re-aim the sensors (steady LED on both eyes) and clear anything blocking the beam — cobwebs, a stray box, or a bike often cause this. Only replace the sensor pair if realignment doesn't clear the fault or a lens is visibly cracked.

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How to fix it

  1. Clear any obstruction and clean the sensor lenses.
  2. Realign both sensors until the indicator LEDs are steady.
  3. Check the sensor wiring and terminal connections at the opener.

Why it happens

Typical signs: 1-1 flash on the opener / sensor LED off or flickering · Door will not close (reverses or will not move) · Must hold the wall button to close

  • Sensors misaligned or blocked Bump, cobweb, or object breaking the beam; LEDs not steady.
  • Sensor wiring disconnected or broken Loose terminals at the opener or a cut/staple-pierced wire.

Other parts sometimes needed

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

More LiftMaster garage door opener codes

1-2 1-2 — Safety sensor wire shorted or reversed 1-3 1-3 — Door control or wire issue 1-4 1-4 — Safety sensors misaligned 1-5 1-5 — No RPM Detected at Start of Movement 1-6 1-6 — Unexpected RPM After Stop at Open 2-1 2-1 — Logic Board Component Failure

All LiftMaster codes → All garage door opener codes →

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: liftmaster.com.